Electronic structure and lattice dynamics of 1T−VSe2: Origin of the three-dimensional charge density wave

To characterize in detail the charge density wave (CDW) transition of 1T−VSe2, its electronic structure and lattice dynamics are comprehensively studied by means of x-ray diffraction, muon spectroscopy, angle resolved photoemission (ARPES), diffuse and inelastic x-ray scattering, and state-of-the-art first-principles density functional theory calculations. Resonant elastic x-ray scattering does not show any resonant enhancement at either V or Se, indicating that the CDW peak at the K edges describes a purely structural modulation of the electronic ordering. ARPES experiments identify (i) a pseudogap at T>TCDW, which leads to a depletion of the density of states in the ML-M'L' plane at T